Method for preparing high-quality pentaerythritol high-carbon fatty acid ester by adopting extraction process

Abstract

The invention discloses a method for preparing high-quality pentaerythritol high-carbon fatty acid ester by adopting an extraction process. The method comprises the following steps: selecting materials; esterifying; filtering; extracting and desolventizing, wherein the material selection link is as follows: high-carbon fatty acid, pentaerythritol and zinc powder are selected; the zinc powder is adopted as a catalyst during esterification reaction, the zinc powder can not only be easily filtered and separated from a product, but also be reacted with the high-carbon fatty acid to generate a trace amount of hydrogen ions, and can generate a strong decolorization effect, so that the high-quality pentaerythritol high-carbon fatty acid ester product cannot be deepened in color and is clean and comfortable; after the zinc powder is filtered, filtered crude pentaerythritol high-carbon fatty acid ester is sufficiently stirred and mixed by using methanol with the volumetric water content of 5%-15%, the high-carbon fatty acid is dissolved in the methanol, the pentaerythritol high-carbon fatty acid ester cannot be dissolved in the methanol, after the quiescent sedimentation is carried out, a methanol solution floats on an upper layer due to light specific gravity, the pentaerythritol high-carbon fatty acid ester is sedimented on a lower layer due to heavy specific gravity, and the high-quality pentaerythritol high-carbon fatty acid ester is obtained by removing the methanol solution.

Description

technical field [0001] The invention relates to a method for preparing pentaerythritol high-carbon fatty acid esters through esterification by using high-carbon fatty acids and pentaerythritol as raw materials, in particular to a new process for purifying pentaerythritol high-carbon fatty acid esters through an extraction process. Background technique [0002] The ester formed by esterification of high-carbon fatty acid (fatty acid with carbon chain ≥ 18) and pentaerythritol is an important additive for engine lubricating oil, metal high-temperature processing oil, flame-resistant hydraulic oil, chemical fiber oil, etc., and can also be used as a high-temperature heat transfer oil. base oil. It is characterized by low freezing point (<-60°C), good fluidity at low temperature, high flash point (≥340°C) and excellent heat resistance. Its reaction formula is: [0003] [0004] However, pentaerythritol has four hydroxyl groups, and the product after esterification contain...

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Problems solved by technology

[0005] To remove free high-carbon fatty acids from esterified products, the alkali refining method cannot be used, because the product has a high viscosity, and it is difficult to separate the fatty acid sodium soap and ester after alkali refining, so that the production operation cannot be carried out.

Use distillation to remove high-carbon fatty acids, because the distillation temperature is greater than 250 ° C, it will cause cracking of the product and produce odor

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